In almost every case, yes — you need a permit to replace windows in California. Section 105.1 of the California Building Code requires a permit before an owner alters or replaces a building component, and windows are part of the exterior envelope that affects structural integrity, fire safety, and energy performance.1ICC Digital Codes. California Building Code, Title 24, Part 2 – Section 105.1 Even a like-for-like swap of one unit for another typically triggers the requirement.
When a Permit Is Required
Section 105.1 is written broadly. It covers anyone who sets out to “construct, enlarge, alter, repair, move, demolish or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace” a regulated system.1ICC Digital Codes. California Building Code, Title 24, Part 2 – Section 105.1 Replacing a full window unit falls within that language. If you are also changing the size of the opening or modifying wall framing to fit a different window, the review becomes more involved because the structural changes need plan review.
Homeowners often ask whether a same-size replacement is exempt. The code lists certain minor work as exempt, but most California building departments treat a full window unit replacement as permitted work regardless of whether the rough opening changes. Pure maintenance — repairing hardware, replacing a single pane of glass within an intact frame, or redoing weatherstripping — is more likely to be considered ordinary repair. When the line is unclear, call your local building department before ordering materials.
Energy Ratings Your Replacement Windows Must Meet
Title 24, Part 6 sets the energy performance every replacement window has to hit.2California Energy Commission. Building Energy Efficiency Standards Two numbers do most of the work. The U-factor measures how well the window insulates. The Solar Heat Gain Coefficient (SHGC) measures how much solar heat passes through. Lower is better for both.
The 2025 Energy Code, which takes effect for projects in 2026, tightened the prescriptive maximums under Table 150.1-A, and they now vary across California’s 16 climate zones:3ICC Digital Codes. 2025 California Energy Code, Title 24, Part 6 – Section 150.1
- Climate Zones 1, 2, 3, 4, 5, 11, 12, 13, 14, and 16: maximum U-factor of 0.27.
- Climate Zones 6, 7, 8, 9, 10, and 15: maximum U-factor of 0.30.
- Climate Zones 2, 4, and 6 through 15: maximum SHGC of 0.23, with Climate Zone 15 at a stricter 0.20.
- Climate Zones 1, 3, 5, and 16: no prescriptive SHGC requirement.
A home in the San Francisco Bay Area (Climate Zone 3) needs a U-factor of 0.27 and faces no SHGC limit. A home in Los Angeles (Climate Zone 9) needs both the 0.30 U-factor and the 0.23 SHGC. Your building department can tell you which zone your property sits in. Every qualifying window carries a National Fenestration Rating Council (NFRC) label showing these values, and that label is what the inspector reads.4ICC Digital Codes. California Energy Code, Title 24, Part 6 – Section 110.6 There is also a mandatory floor across all climate zones: no window worse than a U-factor of 0.40 can legally be installed anywhere in California.3ICC Digital Codes. 2025 California Energy Code, Title 24, Part 6 – Section 150.1
Safety Rules the Permit Enforces
Egress in Bedrooms
Every bedroom needs at least one window large enough for an occupant to climb out and for a firefighter to come in. California Residential Code Section R310 requires these emergency escape and rescue openings in all sleeping rooms, habitable attics, and basements.5ICC Digital Codes. International Residential Code – Section R310.1
Replacement windows get a narrow break. Under Section R310.2.5, a replacement window in a bedroom is exempt from the minimum opening-size and maximum sill-height requirements if it is the manufacturer’s largest standard window that fits the existing frame or rough opening, provides equal or greater opening area than the old window (or matches its operating style), and is not part of a change of occupancy.6ICC Digital Codes. California Residential Code, Title 24, Part 2.5 – Section R310.2.5 The exemption exists because older openings often cannot accept modern egress dimensions without cutting into the wall. The requirement, though, is to maximize the opening within what you have, not to downsize.
Tempered Glass
Safety glass is required where someone is more likely to fall into or through a window. Section R308.4.3 defines a hazardous glazing location by four overlapping conditions: the pane is larger than 9 square feet, its bottom edge is less than 18 inches above the floor, its top edge is more than 36 inches above the floor, and a walking surface is within 36 inches of the glass.7ICC Digital Codes. California Residential Code, Title 24, Part 2.5 – Section R308.4.3 Windows near bathtubs, showers, hot tubs, stairs, and doors have their own safety glazing rules under other subsections of R308. Specifying tempered glass in bathrooms and near doors is the safe default.
Window Opening Control Devices
Where an operable window sits more than 72 inches above the ground outside and the sill is low enough for a child to reach, the window needs an opening control device that complies with ASTM F2090. These devices limit how far the window opens, generally to less than four inches. Egress windows still need a device that an adult can override quickly, since the window has to open fully in a fire.
Lead Rules for Pre-1978 Homes
If your home was built before 1978, a second layer of regulation applies. The EPA’s Renovation, Repair, and Painting (RRP) rule requires that any contractor working on pre-1978 housing be a lead-safe certified renovator and follow specific containment, cleanup, and disposal procedures.8US EPA. Lead Renovation, Repair and Painting Program Window replacement triggers RRP regardless of how much paint is disturbed, because window channels and sills are among the most common sources of lead dust in older housing.
The RRP rule generally does not apply to homeowners doing work on their own homes. It does apply if you rent out any part of the home, operate a child care facility in it, or buy and renovate for resale.8US EPA. Lead Renovation, Repair and Painting Program Where it applies, your contractor must give you the EPA’s lead hazard pamphlet before work begins and keep compliance records for three years.
HOA and Historic-District Approvals
A city permit is not always the only approval you need. If your home is in a community governed by a homeowners association, the HOA’s architectural review committee may have its own standards for window style, frame material, color, and sometimes manufacturer, and you typically have to submit a separate application and receive written approval before ordering. Violating HOA standards can lead to fines or an order to remove the non-compliant windows.
Homes in designated historic districts face a different hurdle. Many California cities require design review or a certificate of appropriateness before any exterior alteration of a historically significant building. In Santa Barbara, for example, buildings over 50 years old require evaluation by the city’s architectural historian before a window replacement permit is approved, and the preferred approach for historic buildings is repair rather than replacement.9City of Santa Barbara. Window Replacement
What the Application Requires
Most building departments want a packet that includes a window schedule listing dimensions, frame materials, and glass types for every unit being replaced, plus a site plan or floor plan showing where each window sits in the home. That lets the plan reviewer confirm that bedroom windows meet egress rules and that bathrooms and locations near doors have safety glass where required. The application must include the NFRC-rated U-factor and SHGC values for the products you plan to install.
If you are hiring a contractor, you provide their license number and proof of workers’ compensation insurance. If you are doing the work yourself, you sign an owner-builder declaration. Business and Professions Code Section 7044 lets homeowners perform work on their own principal residence without a contractor’s license, provided certain conditions are met, including that they have lived in the home for at least 12 months before the work is completed and that the work is not being done to prepare the home for immediate sale.10Contractors State License Board. Building Officials – Owner-Builder Overview
Permit fees vary by jurisdiction. Small projects may come in under $100; larger multi-window jobs with plan review can run several hundred dollars. Ask your local building department for a fee schedule before you submit.
Hiring a Licensed Contractor
California requires a valid state license for window work. Two classifications fit: the C-17 Glazing Contractor license, which specifically covers glass and window installation, and the B-General Building Contractor license, which covers a broader range of residential construction. Either is acceptable for a window replacement.11Contractors State License Board. CSLB Licensing Classifications
Hiring an unlicensed contractor is risky on both sides. From the homeowner’s side, the practical point is that California law says you are not legally required to pay an unlicensed person for their work, and the unlicensed worker cannot sue you for non-payment.12Contractors State License Board. Consequences of Contracting Without a License Verify any contractor’s license status on the CSLB website before signing a contract.
The Final Inspection
Once installation is finished, you schedule a final inspection. The inspector confirms that the installed windows match what the permit approved: NFRC labels for energy compliance, the tempered glass etching stamp in locations that require safety glazing, and sound flashing and weatherproofing around the exterior. If something is wrong — a missing label, the wrong glass in a bathroom, poor flashing — you correct it and schedule a re-inspection.
If You Skip the Permit
Three things tend to happen, and the financial ones land hardest.
Penalties come first. Licensed contractors who violate the code face civil penalties of up to $8,000 per violation from the Contractors State License Board, plus an order to pay permit fees and any local penalties.13Contractors State License Board. Building Code Complaint Many jurisdictions charge double or triple the original permit fee as an investigation fee when unpermitted work surfaces after the fact.
Insurance exposure comes next. Homeowners policies commonly exclude damage arising from unpermitted construction. If a poorly installed window leaks and causes mold or structural rot, the insurer may deny the claim on that ground.
Then there is resale. California Civil Code Section 1102 requires most residential sellers to complete a Transfer Disclosure Statement covering known material facts about the property, and unpermitted renovations fall within that obligation. A buyer’s inspector or title company may flag the work, which can lead to price renegotiation, delayed closing, or a requirement that you retroactively permit the work and bring it up to current code before the sale can close.